In a patent reference 1, there is disclosed a structure in which a wheel speed sensor is supported by a bolt on a bracket for supporting a wheel axle. The wheel speed sensor is made of resin and includes an oblong fixing section to which a sensor cable is attached, and a sensor section passing through a sensor attachment hole of the bracket from the fixing section. Slit apertures of a pulsar ring arranged in an interior of the bracket are detected by a tip of the sensor section.